Геохронология мезозойского щелочного магматизма для Тыркандинской и Амгинской тектонических зон (Алданский щит): новые U-Pb и Ar-Ar данные

Translated title of the contribution: Geochronology of the Mesozoic alkaline magmatism of Tyrkanda and Amga tectonic zones (Aldan shield): New U-Pb and Ar-Ar data

A. Ponomarchuk, I. R. Prokopyev, A. G. Doroshkevich, D. Semenova, A. A. Kraychenko, A. I. Ivanov

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The territory of the Aldan-Stanovoi Shield is a large industrial region in which gold mining objects have been associated with the manifestation of late Mesozoic alkaline magmatism. Ore-bearing alkaline magmatism on the Aldan shield occurs in the age range of 160-115 Ma and is represented by a wide range of high-potassium rocks: alkaline syenites and syenite-porphyries, monzonites, leucitic and nepheline syenites, lamprophyres, biotite pyroxenites and shononites, as well as alkaline and and granitoids. Five superterrains are distinguished in the structure of the Aldan-Stanovoi shield: the West Aldan superterrane, the Central Aldan composite terrane, the East Aldan composite terrane and Uchursky, as well as the Tyndinsky and Chogarsky superterrains. The composite terranes of the Aldan-Stanovoi shield, in turn, are divided by zones of tectonic melange: Amga, Kalarskaya and Tyrkanda.
In this work, we studied petrography, Ar-Ar, and U-Pb geochronology of Mesozoic alkaline magmatism of the Tyrkanda and Amga tectonic zones using the example of the Dzheltulinsky and Verkhneamginsky massifs, respectively. The formation of the Dzheltullinsky massif of the Tyrkanda zone of tectonic melange occurred in the range of 121-111 Ma. The obtained mineralization age of the Dzheltulinsky massif - 121.4 +/- 2.3 Ma - coincides with the formation of the early phases - leucocratic syenites and syenite-porphyry.
The range of Mesozoic alkaline magmatism of the Amga zone of tectonic melange of 139-117 Ma is specified. The experimentally obtained age-specific U-Pb zircons from the alkaline rocks of the Verkhneamginsky massif indicate the presence of three age clusters: 1.9-2.1 billion years, 2.4-2.6 billion years, and 2.7-2.9 billion years. Moreover, approximately 70% of the points correspond to the second group of ages. These age intervals coincide with regional episodes of intraplate magmatism of the Aldan-Stanovoi shield, and may indicate the possible evolution of an ancient mantle source.
Translated title of the contributionGeochronology of the Mesozoic alkaline magmatism of Tyrkanda and Amga tectonic zones (Aldan shield): New U-Pb and Ar-Ar data
Original languageRussian
Article number1
Pages (from-to)6-24
Number of pages19
JournalГеосферные исследования
Issue number4
Publication statusPublished - Dec 2020



State classification of scientific and technological information

  • 38 GEOLOGY

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